The goal of this investigation is to study the antigens, particularly lipopolysaccharide, associated with the outer cell membrane of N. gonorrhoeae and their relationship to human immunity. Bactericidal antibodies have been shown to develop in women who have clinically severe pelvic inflammatory disease; these antibodies have also been demonstrated in the sera of women with prolonged uncomplicated mucosal infection. In addition, these antibodies have been detected in the majority of patients with disseminated infection despite the resistance of these strains to the bactericidal action of normal human sera. In contrast to this apparent paradox, the sensitivity of PID strains to normal human sera predicts the development of bactericidal antibodies in immune sera; this inhibition is antibody specific and not anticomplementary. Lipopolysaccharide antigens, their derivatives, and other immunologically important antigens will be harvested from large batches of organisms. Chemical and physical techniques will be used to isolate, purify, and characterize the antigens. Highly sensitive immunologic assays will be developed and employed to detect antibodies, directed against the important antigens. These assays will also be used to detect antigens present in the clinical specimens. The serologic specificity of cell wall lipopolysaccharides and their derivatives will be studied in attempts to develop a serologic typing scheme for N. gonorrhoeae. Continued examination of normal sera and sera from patients with various types of gonococcal infections will be performed to identify specific immunologic responses. Important clinical and epidemiologic questions will be answered by jointly identifying gonococcoal antigens and their corresponding immunologic activity. Antigens that might elicit a protective response to infection will be identified and if suitable, will be studied for use as a vaccine.